Most custom AR builds often start with a purchase of a lower receiver. After that, it’s pretty much picking out and selecting the components you want that will work with your build and assembling everything. But what if you wanted to make a truly custom AR? One that foregoes the conventional terms of what a firearms “part” is? Well, once again, we have our good friend and dedicated reader Stubbs here to show us the way it’s done. Stubbs is proud to introduce his latest DIY creation, the StAr-15 Open Source AR15 Upper Receiver Firearm. The goal of the StAr-15 is to take the general operating principle of the “standard” AR-15 rifle and make it as inexpensive as possible and also avoid any registered firearms parts. Today we’ll be taking a look at the StAr-15 and how Stubbs cobbled this random assemblage of parts into a functioning DIY firearm.

More of Stubbs’ Evil Creations @ TFB:

• The Pipe Hitter: TFB Reader Makes a DIY 37MM Launcher
• Oh God, He’s Done it Again but This Time it’s Double Trouble – TFB Reader’s Double Barrel AR-15
• The Extendo Extender – 3D Printed 20-Round Extension For Schmeisser S60 Magazines

The StAr-15 Open Source AR15 Upper Receiver Firearm

The StAr-15 was inspired and maybe even blatantly reverse engineered from a Sten I that Stubbs acquired. Some of you clever readers may have already noticed the similarities.

The St-Ar (Sten/Sterling/Stubbs)-(Armalite (Pattern) Rifle 15) is an open source firearm based on an extremely simplified AR15. The BATFE has many times expressed a desire to redetermine what constitutes a firearm to classify an ar15 upper reciever as a regulated part, and some companies upper recievers themselves are already regulated as firearms, making one assembled gun two separate regulated firearms each subject to tax.

After much backlash they rescinded the redefinition of the AR15 as a controlled split reciever firearm and grandfathered all existing firearms of this style.

This is not to say they will heed forever. If at any point they double back feel relieved knowing an AR15 upper will always be avalable in some form in the same manner a lower can be fabricated at home. All you need is your trusty aluminium tube and a 1.250×18 die.

The AR-15 Simplified

As you can see from the photos so far, the StAr-15 looks quite odd but at its core, it’s still functioning off of a direct gas impingement system. It won’t be winning any beauty contests but I don’t think Stubbs set out to make this thing pretty – just cheap. Almost everything found on a regular AR can be found on the StAr-15 with a few notable omissions. First, there is no AR-15 upper/lower or buffer tube. This eliminates the need for an end plate, castle nut, buffer retainer, detents, and takedown pins – basically all the small parts you lose in your garage putting together one in the first place.

Second, there is no forward assist, dust cover, or any of their associated small parts. Lastly, there is no charging handle. In Stubb’s instance, the charging handle has been replaced by a wine cork attached to the top of the gas key. This, according to Stubbs is the only proprietary part.

In as far as the tools needed to put this thing together, all you really need is a Magpul BEV block, and a Wheeler Armorers Wrench for the assembly portion. Other household garage tools are suitable for the rest of the assembly and cutting/finishing you’ll need and in case you couldn’t have guessed yet, you’ll need a 3D printer to get the lower made as well as the Thompson style forward grip.

The lower and upper are drilled and tapped to make use of some standard quarter-inch bolts to hold them together. Honestly, this is quite a simple solution and something a number of other firearms already do in some shape, form or fashion. The only downside to this that I can see is that any administrative cleaning that needs to be done will require the use of a tool to take the upper and lower apart.

Stubbs mentioned that the most expensive tool to accomplish this job outside of what he already had was the purchase of a 1.250×218 die for putting the threads on the tube to fit the barrel nut. Even with this cost rolled into the project, he told me that the entire thing cost less than $350 including parts he already had. Considering he’s using a cheap bolt carrier group, standard government profile barrel, and some other off-the-shelf non-regulated parts, I find this to be extremely impressive. The most unique item on his list is the aluminum pipe which cost about $40 but in reality, it’s much less since Stubbs only had to use a short length of it for this build.

Parts breakdown as presented to me by Stubbs:

• 16.1″ 5.56 MidLength AR-15 / M4 A2 Government .750 1:8 Barrel: $79.95
• Bolt Carrier Group: $64.99
• UZI Stock: $28.95
• 36″ Aluminum Tube: ($17.93 + $27.54 Shipping) Multiple buffer tubes can be made from this one piece.
• 1.250×18 die: $75.99
• Wine Cork: $20 for the bottle

The rest of the parts are pretty standard AR-15 stuff which most of you probably have an entire box full of sitting around somewhere in the garage (and if you don’t, you should).

So Does it work?

According to Stubbs, his StAr-15 works pretty great and considering it’s only about $350 worth of stuff and his time, I find that quite the accomplishment. For those wondering, the StAr-15 as configured in the pictures with the Uzi stock, and forward grip weighs in at 6.5lbs so you’re not really gaining anything in the weight department despite there being no charging handle, a stripped down upper receiver and making use of a 3D printed lower. Another downside of the design is the exposed gas tube which travels out of the rear of the barrel nut and directly interfaces with the gas key.

I asked Stubbs if this design lead to a bunch of gas getting spit right in his face when firing it. Since Stubbs is wrong-handed (a lefty), he said that he’s already used to gas getting in his face from the BGC and with the exposed gas key the gas has tended to blow out of the top. What he said in his own words is that “it farts” but what I think he means by this is that it’d be impossible to shoot it without eye protection. Not an optimal design but once again this is a very cheap AR made at home using a combination of hardware store parts and other commonly available and unregulated firearms parts.

If Stubbs really wanted to, he could probably make his own barrel out of a blank which might reduce costs further. He could have also probably 3D printed the handguard, and pistol grip and left out the UZI stock as well to reduce the cost of the build further. I’m just impressed that his cacophony of parts even functions. I’d like to hear your thoughts as I’m sure Stubbs would. What do you think of the StAr-15 rifle? What would you do differently and how would you tackle a project like this if you were trying to make a super inexpensive AR-15? Let us know down in the comments!

More work on the StAr-15 is already being done by what Stubbs calls “co-conspirators” and these efforts are working towards making simplified and substitute parts for the StAr-15 and there might even be some interesting developments being made using the StAr-15. Sneak preview below.

Photo Credit: Reason Arms

All photos (unless otherwise stated) are credited to Stubbs of the TFB Discord.